Step-by-step automatic tuning control



Sept, 14, 1948. G. 1.; sANsBuRY f 2,449,178

v STEP-Y-s'rEP AuTouAfrIc TUNING con'raon Filed haren e. 1947 4 sheets-sunt 1 G. L. sANsBuRY 2,449,178

' STEP-BY-STEP AUTOMATIC TUNING CONTROLV n sept. 14,1948.

4 Sheets-Sheet 2 Filed arch 6, 1947 A |NvEN'roR GEORGE L. SANSBlRY BY K/ Av vRN G. L, AsANsBuRY Bnsrsr AuTouA'rIc A'mmm connor.

Sept. 14, 1.948.

STE?- 4 Sheets-Sheet 3 Filed March 6. 1947 iNVNTR CQGE L SANSBURY @Y @A gf 11u RNS' lSW 1411948 G. L sANsBuRY l y 2,449,178 STEP-BY-STEP AUTOMATIC TUNING CONTROL INVENTOR GEORGE I.. SANSB URY Patented Sept. 14, 1948 George L. Sansbury. Cedar Rapids, Iowa, assignor to Collins a corporation of Iowa Application Much s, i941, serial No. '132,696

This invention relates to remote control apparatus and more especially to arrangements for selectively'rotating a control `shaft to any one of a number of desired positions.

A principal object of the invention is to pro,

vide a simplified and rugged device for electromagnetically rotating a control shaft to any one I of a number of desired positions.

Another object is to provide a novel combination of electric circuits and electromagnetic and mechanical controls whereby a device such as a radio tuning or control unit, can be remotely set at any desired position and with a high order of accuracy.

An additional object is to provide a simplied and improved electromagnetic step-by-step motor unit for translating received selective impulses into angular positions of ashai't to be controlled."

A feature of the invention relates to an improved electromagnetically controlled-ratchet device for operating a control shaft in a step-by# step manner whereby the shaft is positively driven Y step-by-step motor arrangement for electric control devices which unit comprises an electromagnetic solenoid with a novel mechanical arrangement for converting the reciprocating movement of the solenoid plunger into step-by-step rotary movements of a shaft.

A still further feature relates to the novel organization, arrangement and relative interconnection of parts which cooperate to provide an improved automatic shaft control system.

Other features and advantages not specifically enumerated will be apparent after a consideration of the following detailed descriptions and the appended claims. j

In the drawing,

Fig. 1 is a front view of the device, with the front cover plate removed, to show the interior construction more clearly.

Fig. 2 isy Ia, left-hand side view of Fig. 1 the enclosing housing broken away.

Fig. 3 is a right-hand side view of Fig. 1.

Fig. 4 is an 'exploded view of the solenoid niotor device incorporated vin the unit of Pigs. l to 3.

with

Radio Company, Cedar Rapids, Iowa,

. 13 Claims. (Cl. 318-21) Fig. 5 is a sectional view of the solenoid motor device.

- Figs. 6 and 7 are respective fragmentary views of part of the solenoid motor device to explain its operation.

Fig. 8 is a composite electrical and mechanical diagram showing an'automatic shaft positioning system embodying the device of Figs. 1 to 7.

The device is enclosed Within a metal box-like housing l0. Fitted within the housing is a rigid metal frame work il, of substantially G-shaped form and having at its forward ends downwardlyy depending lips i2, i3, and an upwardly extending lip I4. Attached to these lips by screws l5 is a front plate I6 which carries certain of the parts to be described. Suitably fastened to the rear wall of frame li. for example by screws l1. is a solenoid motor unit I8, which is shown in detail in Figs. 4 and 5. This unit comprises a ilat ironidisc 9 to which is welded or otherwise fastened a central annular soft iron pole piece 20. Disc 9 is tightly fitted within the rim 2| of an iron casing thus providing an annular space within which is located a solenoid coil or winding 22. Disc 9 at its central opening is iltted with a bearing washer or sleeve 23 for the plunger shaft 24. which carries at its upper end a circular soft iron magnetic core member 25 fastened to an iron disc 26. The shaft 24 has a circular recess adjacent its lower end to receive a. collar or washer 2 1 to limit the upward movement of the shaft e 24. Thus, shaft 24 and disc 26 are capable of limited unitary movement in an axial direction and are capable of rotation around this axis. The magnetic core 25 is slightly smaller in diameter than the circular opening 28 in the casing 2i Consequently, when the winding 22 is energized,

` it pulls the core 25 and its attached disc 26 downwardly as shown in Figs. 2 and 5. In order to convert the reciprocating motion of shaft 24 into a rotary motion, the Wal1 29 of casing 2| has three inclined recesses 30, 3i, 32, and the adjacent face of disc 26 has a similar set of inclined recesses 33, 34, 35. These recesses are arcuate and are equi-distant from the center of the disc and are spaced apart on centers approximately degrees, each recess being approximately 22% degrees in arcuate length. A set of three metal balls I6 are provided, each ball riding in the corresponding aligned recesses 30-33, 3l-34, $2- ll. By means of a coil spring 31 described hereinbelow, the disc 26 is rotated to a normal or rest position (Fig. 6), wherein the relation of the cooperating recesses lll-33, etc., and the respective ball bearings is shown in Fig. 6, from which it will be seen that disc ze is spaced from the casing wall 29 by a certain distance, and the rotation of the disc 26 with respect to the casing is limited by the engagement of the ball 36 with the opposed shoulders 88, 36, of its respective recesses as shown in Fig. 7. Consequently, when the energization of winding 422, the'disc rotates through an angular distance D which is approximately equal to twice the length of each recess.

l the disc 26 is pulled downwardly as a result of 4 held in place thereon by a split ring 1l which seats in, a grooveat the reduced end of shaft 41. Attached to member Il is a lipped member 13a which receives the end oi a bowed leaf spring y 13, the other end `oi whtch is pivotally attached to the end of arm 16, so as to constitute with y that arm, in eiiect, 'a toggle which is capable of instantly snapping arm 1I in one direction or Thev angular rotation of disc 26 is limited bythe f ball 36 engaging the opposed shoulders 46, 4I, in the respective recesses (Fig. 7). Thus, for each energization of the solenoid winding,l the disc 26 Y is rotated through an angle of approximately 45 degrees and when the solenoid is deenergired the disc 26 is returned to its normal or rest position by spring 31.

Disc 26 has attached thereto an arm 42 carrybeing against the force of spring 31 whichl has one end 49 looped around the arm 42, which carries pawl 43 and the outer turn engages a ilxed stop 31a. The opposite end 5| of spring 31 ilts over a xed pin 52 on sleeve 46. For the purpose of locking wheel 46 in its selected position, a stop pawl 53 is pivoted on stub shaft 54 having one end anchored to plate I6. Ordinarily,l in devices of this type, reliance would be placed upon the spring 55 to maintain the pawl 53 in stopping engagement with the ratchet wheel, and while for certain purposes this may be found satisfactory, I have found that in systems to be described in connection with Fig. 6 where extreme accuracy of stopping is required, additional positive means must be provided for locking the wheel 46 in its selected position. For this purpose, disc 26 carries a pin 51 which engages a lip 56 on pawl 53, so as positively to force the locking tooth of pawl 53 in engagement with the selected recess in the wheel 46. On the other hand, when the wheel 46 is about to begin its selective rotation under control of the power driving pawl 43, the pin 51 disengages the lip 58 and pawl 53 is held in contact with the teeth of wheel 46 merely by the spring 55.

Supported' from pawl 53 is a leaf spring 58, which carries a contact 66. Likewise, insulatingly mounted onfthe front wall I6 are a pair of leaf springs 6I, 62, which are clamped at one end betweengintervening insulator spacers 63, 64, 65, by means of a screw 65a which passes through the insulating spacers and through suitable insulating washers (not shown) so as` to prevent short-circuiting of the springs 6i, 62. Also clamped between the spacers 63, 64, and in contact with spring 6i, is a rigid plate 68 which acts as a back stop for spring 62 and limits clockwise rotation of arm 16. Counterclockwise rotation of arm I6 is limited by pin l66, which is mounted on plate' I6. Each of the springs 6I, 62, carries at its upper end respective cooperating contacts. Normally, that is in the position of rest of disc 26 (Fig. l), the contacts on springs 6I, 62, are in engagement. In this position, there is a slight clearance between upper end of spring 62 and the rounded corner 69 of an insulating arm 16, which arm is supported on the end of shaft 41 for free rotation with respect thereto and is the other depending upon which way the toggle is broken. In order to" break the toggle, disc 26l carries two pins 14,' 15. After disc 26 has begun its rotationin the clockwise or power driven direction by means of pawl 43, pin 14 engages arm 16 and causes the toggle to break and snap inj a clockwise vdirection whereby thecontact springs .6|, 62, are separated. On the other hand, when the disc 26 reaches the end of its counterclockwise or return-to-normal direction,

pin 15.,V engages arm 16 and breaks the toggle counterclockwise causing the reengagement of the contact springs 6|, 62. I

Plate I 6 is provided with an opening into which is fitted a rubber grommet 16 through which pass the lead-in wires 11, 18, for the solenoid winding 22, and the various'circuit wires which are connected to suitable connector tabs (not shown) on the anchored ends of the respective leaf springs 59, 6|, 62 and 66.

'I'he operation of the device of Figs. l to '7 will/be clear fromithe ensuing description taken in conjunction 4with.the schematic diagram of Fig. 8, wherein the parts which are the same as thoseof Figs. l to 'I are designated by the same numerals. In Fig. 8,l mechanical connections or engagements between certain of the parts are indicated schematically by heavy or thick lines, whereas the electrical wiring connections are represented by ne lines. As pointed out above, the device is primarily intended to control the rotational `selective setting of any device such for example as a radio tuning element 86 which is arranged to be mechanically coupled to shaft 41 and which is designed to be remotely controlled from a master station 6i at which is located a manually operable multipointselector switch 82.

Merely for explanatorypurposes, it will be assumed that the device 86 is tobe selectively positioned in any one of twelve dinerent angular settings, and for this purpose switch 82 has twelve stationary contacts 84 which are suitably supported in an insulating disc or block 85. Mounted for rotation parallel to the plane of the fixed contacts is a metal disc 81 having a peripheral slot or cutout 88, the Width of which is l slightly greater than'thediameter of the stationary contacts 84, so that when the disc 85 is centered with respect to a bank contact, the edges of the slot 88 entirely clear the said contact. A grounded and iixed brush y86 makes continuous contact with the disc 85. Switch 82 is shown as having'been previously turned so that the #i contact 84 is the only one of the twelve which is ungrounded.

'I'he line finder or` selector switch 83 at the remote point also has a series of twelve stationary contacts 96 which may be supported in an insulation disc 9|. These stationary contacts are connected by individual wires 92 to the correspending numbered contacts of switch 82. operating with the contacts 96 is a metal disc 93 whose diameter is such that it clears the contacts 86, but it carries a-brush or wiper 94 which suc- Ccl f' s s wheel 46 previously described herein, also Vhas aseries of twelve teeth, and twelve corresponding guarra notches to be engagedby the pawl 43. Therefore the ilnal selective positioning of the device 190 is under the conjoint control oi the automatic selector switch 93 and the toothed wheel 49.

It will be assumed that the device 80 is to be automatically moved to a new setting, for example that corresponding to #3 contact of switch 82. For this purpose switch 82 is manually operated to cause slot 88 to register with #3 contact, which removes the ground from the corresponding #3 contact at switch 93. However, ground-is applied to all the remaining .contacts of switch I83 including the previously selected #I contact, whereupon a circuit is traceable from the grounded battery 96, through solenoid winding 22, contacts 6I, 62, conductor 91, brush 95, disc 93, brush 94, contact #I of switch 8'3, to ground at the corresponding #I contact of switch 82. The energlzation of solenoid 22 causes the disc 26 to be rotated in a clockwise direction, thus causing pawl 43 to start rotation of the wheel 46. As'

soon as the disc 26 starts rotating clockwise, 'the member 51 disengages the locking pawl 53 and enables the wheel 46 to be positively driven by wheel, a cooperating driving pawl, and a solenoid having its plunger connected to said pawl and Drovidedvwith means to convert received selected impulses into a composite rectilinear and rotary movementof said plunger, the last-mentioned means comprising a disc,.attached to said plunger and having a plurality of camming guides and a cooperating ball for each guide for converting the reciprocal motion o! saidl plunger into said composite movement, said ydriving pawl being attached to said disc.

2. vAn automatic shaft-positioning arrangement comprising an automatic selector switch, a stepby-step motor -device ior operating said switch andthe shaft to be controlled, an impulsing circuit for said Amotor device completed through the contacts of said selector switch, said motor device comprising a toothed driving wheel and cooperating driving pawl, a solenoid having its plunger connected to said driving pawl, and means to convertV received selec-tive impulses into composite rectilinear and rotary movement of said plunger to drive said toothed wheel positively throughout its entire arcuate movement between each successive selective position of. said switch, the last-mentioned means comprising a disc attacked to said plunger and having a plurality of camming guides and a cooperatingball for each 51, and it is cammed downwardly by the inclined face on the wheel teeth causing the contacts 66 and 61 to be closed, thus providing a parallel ensolenoid disc 26 therefore continues and positivei ly drives the wheel 46 until pawl 53 again drops into the next wheel slot and allows contacts 60i 61, to open, thus removing energizing current from the winding 22. The spring 31 thereupon returns the solenoid disc 26 to its normal or at res position and at the end of this return stroke the arm 10 is engaged by the member 15, causing the toggle switch to be broken in a counterclockwise direction and resulting in the reclosure of contacts 6I, 62. During this return movement or dis-c 26, the wheel 46 is locked against counterclockwise rotation by means of pawl 53. 'I'he above-described sequence of operations continues until the brush 94 iinds the #3 contact which is now ungrounded, whereupon the switch 93 comes to rest as does the toothed wheel 46. At the same time that the cycle of operations is completed, the member 51 reengages the pawl 53 and mefchanically forces it into positive locking engagement with the toothed wheel 46. The device is thereupon positively locked in its selected anA guiar position. From the foregoing, it will be seen that the wheel 4-6 is positively driven from one position to each successive posi-tion. and that it is positively locked between each successive step as distinguished from the conventional pawl op-` erated ratchet wheel, wherein the operating pawl operating said switch and the shaft to b e controlled, said motor device comprising a toothed line nder type,'a step-by-step motor device for c guide for converting the reciprocal motion of said plunger into saidcomposite movement, said driv ingpawl beingattached to said disc. y

Y 3. An automatic shaft-positioning arrangement comprising anA automatic selectorswtchoftheline nnder type, a step-by-step mot-or device for operating said switch and the shaft to becontrolled, an impulsing circuit for said motor device controlled through the contacts of said selector switch, said motor device including a toothed driving wheel andassociated 'driving pawl, a solenoidhaving its plunger connected to said pawl, a spring normallyv tending to turn said plunger around its axis to a rest position, and means responsive to each impulse to rotate said plunger through a predetermined angle suiiicient to drive said wheel positively throughout its entire arcuate length between each successive tooth, said spring being eiectiveupon each deenergization of said solenoid to return .said plunger to its rest position without disturbing the previously set position of said wheel.

4. An automatic shaft-positioning arrangement comprising an automaticrseiector switch having a series of ixed-contactseach allotted to a particular setting of said shaft, said switch having a brush for engagingsaid contacts, a step-by-step motor device forfoperating said switch, an impulsing circuit for said motor device completed through thecontacts of said switch, said motor device comprising a toothed wheel having a tooth for each of said ixed contacts, a driving pawl for said wheel, a rotatable member on which said pawl is carried, a solenoid plunger attached to said member, a solenoid winding for said plunger and connected in said impulsing circuit, and means to convert the reciprocating motion of said plunger into rotary motion of said member to cause said pawl to drive said wheel positively throughout vits entire arcuate travel between each successive selective position of said switch. f

.5. An automatic shaft-positioning arrangement comprising an automatic selector` switch oi the rotary line -ilnder type, a step-by-s-tep motor device for operating said switch, an impulsing circuit for said motor device controlled by the contactsoi said selector switch, said motor device comprising a toothed wheel and cooperating driving pawl, a rotatable member carrying said pawl.

a solenoid having a plunger fastened to said member, at least one inclined guide on one face oi' said member, a ball bearing in said guide, a iixed support on which said ball is arranged to roll while in said guide, and means including said impulsing circuit to energize said solenoid for causing said guide and ball to act as a camming device to translate the reciprocating motion of said plunger directly into a rotary motion o! said member.

6. An automatic shaft-positioning arrangement comprising an automatic selector switch of the rotary type. a step-by-step motor device for operating said switch, an impulsing circuit for said motor device controlled through the contacts of said switch, said motor device comprising a toothed wheel and cooperating driving pawl, a rotatable member carrying said pawl, a solenoid having a plunger which is attached to said member, a plurality of pairs-of cooperating inclined guides in said member and said support. a ball bearing in each pair of guides, and means including said impulsing circuit to energize said solenoid for causingy said guides and balls to coact as camming devices to translate the reciprocating motion of said plunger directly into a rotary motion oi said member.

'1. An automatic shaft-positioning arrangement according to claim 6 in which each cooperating pair oi said inclined guides have opposite inclinations with respect to the rotational axis of said member. Y

8. An automatic shaft-positioning arrangement according to claim 6 in which a spring is provided for restoring said member to a normal positionai'ter each deenergization of said solenoid without disturbing the previous set position of said wheel.

9. An automatic shaft-positioning arrangement according to claim in which a separate stop pawl is provided for said wheel, and said rotatable member carries a'priection which me-` chanically engages said stop pawl to lock said wheel positively when it reachesV its normal position.

10. An automatic shalt-positioning arrangement according to claim 5, in which a separate stop pawl is provided for saidwheel and having a spring for maintaining it in contact with the teeth of said wheel, and said rotatable member carriesa projection which mechanically vengages said stop pawl to lock it mechanically against said wheel when the latter is in a rest position.

11. An automatic shaft-positioning arrangement comprising an automatic selector switch, a step-by-step motor device for operating said switch and the shaft to be controlled. said motor device comprising a toothed wheel, a cooperating t 8 normally closed when said wheel is in its rest position, an impulsing circuit'ior said solenoid initially completed through said pair oi' contacts and through the contacts oi said selector switch,

and a substitute switching circuit comprising a pair oi.' contacts which are normally open when said'wheel is at rest and which are closed while the wheel is moving between successive positions.

controlled and operated by said driving pawl. a

stop pawl for said toothed wheel, an impulsing circuit for the solenoid comprising the contacts of said selector switch and a pair of normally closed contacts associated with said wheel, another pair of normally open contacts for said wheel also providing a substitute switching circuit for said solenoid independent of said selector switch, a snap-acting member for opening said pair of normally closed contacts in response to the initial movement of said wheel, said snap acting member being operated mechanically by the rotary motion of said plunger when said plunger is rotating away from its rest position, and means carried by said plunger for operating said snap-acting switch member in the opposite direction to close said pair of normally closed conftacts when said plunger reaches its rest position.

13. An automatic shaft-positioning arrangement comprising a selector switch of the line finder type, a step-by-step motor for driving said switch, said motor comprising a solenoid plunger, a member attached to said plunger and having means to convert the reciprocating motion of the plunger into a rotary motion oi' said member, a toothed wheel fastened to the shaft of said selectr switch, a driving pawl for said 4toothed wheel and carried by said member, a snap-acting switch, means carried by said member for operating said snap-acting switch to close said contacts when said member is at its position o! rest, a projection carried by said member for operating said snap-acting switch to open said contacts when said member begins its rotary motion, a stopping pawl for said toothed wheel, and a pair of contacts closed by said stopping pawl for substantially the entire interval while said toothed wheel is moving between successive rotary positions, and further means carried by said member -for mechanically locking said stopping pawl driving pawl and a cooperating stopping pawl,

a solenoid for operating saiddriving pawl, said solenoid having a plunger arranged for reciproaainst said toothed wheel when said member is in its rest position.

GEORGE L. SANSBURY.

REFERENCES CITED The following references are of record in the ille of this patent:

cation and rotation, a disc attached to said plung- Y er, a plurality of camming guides and cooperating balls for turning said disc through a predetermined angle in response to energization of said solenoid, said pawl being attached to said disc, a pair of contacts associated with said wheel and UNITED STA'IV'ES PATENTS Number 2,362,690 

